KASAN: global-out-of-bounds Read in precalculate_color

KASAN: global-out-of-bounds Read in precalculate_color

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    d7688697 Merge tag 'for-linus' of git://git.kernel.org/pub..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=125118a2e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=121b4285bac421fe
dashboard link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=119c517ae00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: global-out-of-bounds in precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
Read of size 1 at addr ffffffff884787bf by task vivid-000-vid-c/8948

CPU: 1 PID: 8948 Comm: vivid-000-vid-c Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x197/0x210 lib/dump_stack.c:118
  print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:634
  __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
  precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
  tpg_precalculate_colors drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:1093  
[inline]
  tpg_recalc+0x561/0x2850 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2118
  tpg_calc_text_basep+0xa1/0x290  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2136
  vivid_fillbuff+0x1a5f/0x3af0  
drivers/media/platform/vivid/vivid-kthread-cap.c:466
  vivid_thread_vid_cap_tick+0x8cf/0x2210  
drivers/media/platform/vivid/vivid-kthread-cap.c:727
  vivid_thread_vid_cap+0x5d8/0xa60  
drivers/media/platform/vivid/vivid-kthread-cap.c:866
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the variable:
  sin+0x17f/0x280

Memory state around the buggy address:
  ffffffff88478680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffffffff88478700: 00 00 00 00 00 00 00 00 01 fa fa fa fa fa fa fa
> ffffffff88478780: 00 00 06 fa fa fa fa fa 04 fa fa fa fa fa fa fa
                                         ^
  ffffffff88478800: 05 fa fa fa fa fa fa fa 05 fa fa fa fa fa fa fa
  ffffffff88478880: 00 00 fa fa fa fa fa fa 00 00 00 00 00 00 fa fa
==================================================================


---
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Re: KASAN: global-out-of-bounds Read in precalculate_color

[syzbot]

syzbot has bisected this bug to:

commit 7594bf37ae9ffc434da425120c576909eb33b0bc
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Mon Jul 17 02:53:08 2017 +0000

     9p: untangle ->poll() mess

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15e323a6e00000
start commit:   d7688697 Merge tag 'for-linus' of git://git.kernel.org/pub..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13e323a6e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=121b4285bac421fe
dashboard link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=119c517ae00000

Reported-by: syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com
Fixes: 7594bf37ae9f ("9p: untangle ->poll() mess")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: KASAN: global-out-of-bounds Read in precalculate_color

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    46cf053e Linux 5.5-rc3
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11932ce1e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ed9d672709340e35
dashboard link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14861a49e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1794423ee00000

The bug was bisected to:

commit 7594bf37ae9ffc434da425120c576909eb33b0bc
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Mon Jul 17 02:53:08 2017 +0000

     9p: untangle ->poll() mess

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15e323a6e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=13e323a6e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+02d9172bf4c43104cd70@syzkaller.appspotmail.com
Fixes: 7594bf37ae9f ("9p: untangle ->poll() mess")

==================================================================
BUG: KASAN: global-out-of-bounds in precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
Read of size 1 at addr ffffffff88b3d3f9 by task vivid-000-vid-c/9278

CPU: 0 PID: 9278 Comm: vivid-000-vid-c Not tainted 5.5.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x197/0x210 lib/dump_stack.c:118
  print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:639
  __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132
  precalculate_color+0x2154/0x2480  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:942
  tpg_precalculate_colors drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:1093  
[inline]
  tpg_recalc+0x561/0x2850 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2118
  tpg_calc_text_basep+0xa1/0x290  
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2136
  vivid_fillbuff+0x1a5f/0x3af0  
drivers/media/platform/vivid/vivid-kthread-cap.c:466
  vivid_thread_vid_cap_tick+0x8cf/0x2210  
drivers/media/platform/vivid/vivid-kthread-cap.c:727
  vivid_thread_vid_cap+0x5d8/0xa60  
drivers/media/platform/vivid/vivid-kthread-cap.c:866
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the variable:
  kbd_keycodes+0x119/0x760

Memory state around the buggy address:
  ffffffff88b3d280: fa fa fa fa 00 00 04 fa fa fa fa fa 00 00 00 00
  ffffffff88b3d300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffffffff88b3d380: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
                                                                 ^
  ffffffff88b3d400: 00 00 00 00 07 fa fa fa fa fa fa fa 00 00 00 00
  ffffffff88b3d480: 00 fa fa fa fa fa fa fa 02 fa fa fa fa fa fa fa
==================================================================

Re: KASAN: global-out-of-bounds Read in precalculate_color

[syzbot]

syzbot suspects this issue was fixed by commit:

commit dfd402a4c4baae42398ce9180ff424d589b8bffc
Author: Marco Elver <elver@google.com>
Date:   Thu Nov 14 18:02:54 2019 +0000

    kcsan: Add Kernel Concurrency Sanitizer infrastructure

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13eb65d6900000
start commit:   46cf053e Linux 5.5-rc3
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=ed9d672709340e35
dashboard link: https://syzkaller.appspot.com/bug?extid=02d9172bf4c43104cd70
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=147e5ac1e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14b49e71e00000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: kcsan: Add Kernel Concurrency Sanitizer infrastructure

For information about bisection process see: https://goo.gl/tpsmEJ#bisection